LAC-MEGANTIC, Quebec — A Quebec town devastated when a runaway oil tanker train ignited explosions and fires braced today for what authorities assured would be a rising death toll as fire crews tried to reach the hardest-hit areas more than two days after the disaster. Five were dead and about 40 people remained missing.

Firefighters were focusing their efforts today on two oil-filled cars, dousing them with water and foam in an attempt to keep them from overheating and exploding.

Quebec provincial police Sgt. Benoit Richard said this morning there was no searching overnight because the situation remained too dangerous.

He said only a small part of the devastated scene has been searched as firefighters made sure all flames were out.

Many of those missing were believed to have been drinking at a popular downtown establishment when the explosions occurred and rescuers were still not able to reach the bar, Richard said.

The growing number of trains transporting crude oil in Canada and the United States had raised concerns of a major derailment, and this one was sure to add to the debate over a proposed cross-U.S. oil pipeline that Canada says it badly needs.

All but one of the train’s 73 tanker cars were carrying oil when they somehow came loose early Saturday morning, sped downhill nearly seven miles into the town of Lac-Megantic, near the Maine border, derailed and began exploding one by one. At least five blew.

“This is an unbelievable disaster,” said Canadian Prime Minister Stephen Harper, who toured the town Sunday and compared it to a war zone.

“This is an enormous area, 30 buildings just completely destroyed, for all intents and purposes incinerated. There isn’t a family that is not affected by this.”

The downtown bar area had been bustling at the time of the crash. Quebec provincial police Sgt. Benoit Richard said only a small part of the devastated scene had been searched Sunday as firefighters made sure all flames were out.

About a third of the community of 6,000 was forced out of their homes.

Locals were convinced the death toll was far higher than five. Anne-Julie Huot, 27, said at least five friends and about 20 acquaintances remained unaccounted for.

“I have a friend who was smoking outside the bar when it happened, and she barely got away, so we can guess what happened to the people inside,” Huot said. “It’s like a nightmare.”

A coroner’s spokeswoman said it may not be possible to recover some of the bodies because of the intensity of the blasts.

Spokeswoman Geneviève Guilbault said the bodies are so badly burned that identifying them could take a long time. She said none of the five bodies that have been found so far have been identified and two have been sent to Montreal for further analysis. All of the autopsies will be conducted in Montreal because there is no laboratory in town.

For the second day in a row, she urged families of the missing to come forward with details that could help them identify the bodies, such as tattoos, dental records, or objects that would contain the DNA of the deceased.

The train’s oil was being transported from North Dakota’s Bakken oil region to a refinery in New Brunswick. Because of limited pipeline capacity in the Bakken region and in Canada, oil producers are increasingly using railroads to transport oil to refineries.

The Canadian Railway Association recently estimated that as many as 140,000 carloads of crude oil will be shipped on Canada’s tracks this year — up from 500 carloads in 2009. The Quebec disaster is the fourth freight train accident in Canada under investigation involving crude oil shipments since the beginning of the year.

Harper has called railroad transit “far more environmentally challenging” while trying to persuade the Obama administration to approve the controversial Keystone XL oil pipeline from Canada to the Gulf Coast. Greenpeace Canada said Sunday that federal safety regulations haven’t kept up with the enormous growth in the shipment of oil by rail.

Officials with the Montreal, Maine & Atlantic Railway said that despite the disaster, they feel transporting oil by rail is safe.

“No matter what mode of transportation you are going to have incidents. That’s been proven. This is an unfortunate incident,” said Joe McGonigle, Montreal, Maine & Atlantic Railway’s vice president of marketing.

He said the company believes the train’s brakes were the cause. “The train was parked, it was tied up. The brakes were secured. Somehow it got loose,” he said.

McGonigle said there was no reason to suspect any criminal or terror-related activity.

Local fire Chief Denis Lauzon said firefighters in a nearby community were called to a locomotive fire on the same train a few hours before the derailment. McGonigle confirmed the fire department showed up after the first engineer tied up and went to a hotel.

“We know that one of our employees from our engineering department showed up at the same time to assist the fire department. Exactly what they did is being investigated, so the engineer wasn’t the last man to touch that train, we know that, but we’re not sure what happened,” McGonigle said.

Transportation Safety Board investigator Donald Ross said the black box of the locomotive has been recovered, but officials haven’t been able to access much of the site.

“We’ve had a very good safety record for these 10 years,” said Edward Burkhardt, the president and CEO of Rail World Inc., the parent company of Montreal, Maine & Atlantic Railway. “Well, I think we’ve blown it here.”